CONCEPT_ANCESTOR table

The CONCEPT_ANCESTOR table is designed to simplify observational analysis by providing the complete hierarchical relationships between Concepts. Only direct parent-child relationships between Concepts are stored in the CONCEPT_RELATIONSHIP table. To determine higher level ancestry connections, all individual direct relationships would have to be navigated at analysis time. The CONCEPT_ANCESTOR table includes records for all parent-child relationships, as well as grandparent-grandchild relationships and those of any other level of lineage. Using the CONCEPT_ANCESTOR table allows for querying for all descendants of a hierarchical concept. For example, drug ingredients and drug products are all descendants of a drug class ancestor.

This table is entirely derived from the CONCEPT, CONCEPT_RELATIONSHIP and RELATIONSHIP tables.

Field

Required

Type

Description

ancestor_concept_id

Yes

integer

A foreign key to the concept in the concept table for the higher-level concept that forms the ancestor in the relationship.

descendant_concept_id

Yes

integer

A foreign key to the concept in the concept table for the lower-level concept that forms the descendant in the relationship.

min_levels_of_separation

Yes

integer

The minimum separation in number of levels of hierarchy between ancestor and descendant concepts. This is an attribute that is used to simplify hierarchic analysis.

max_levels_of_separation

Yes

integer

The maximum separation in number of levels of hierarchy between ancestor and descendant concepts. This is an attribute that is used to simplify hierarchic analysis.

A path between two concepts can be characterized by the sequence of relationships that need to be traversed in order to reach a descendant concept from an ancestor concept.

For example, for concepts

descendant_concept_id

descendant_concept_name

ancestor_concept_id

ancestor_concept_name

min_levels_of_separation

max_levels_of_separation

313217

Atrial fibrillation

321588

Heart disease

3

4

the shortest path in concept_relationship will be :

313217 Atrial fibrillation Is a 4226399 Fibrillation Is a
44784217 Cardiac arrhythmia Is a 321588 Heart disease

the longest:

313217 Atrial fibrillation Is a 4068155 Atrial arrhythmia Is a
4248028 Supraventricular arrhythmia Is a 44784217 Cardiac arrhythmia Is a
321588 Heart disease

Conventions

Each concept is also recorded as an ancestor of itself.

Only valid and Standard Concepts participate in the CONCEPT_ANCESTOR table. It is not possible to find ancestors or descendants of deprecated or Source Concepts.

Usually, only Concepts of the same Domain are connected through records of the CONCEPT_ANCESTOR table, but there might be exceptions.